Integration of Battery Energy Storage with a Transformer-less Solar PV Micro-inverter

The conventional solar PV micro-inverters are designed to be operated in grid connected mode and do not possess any provision for energy storage. In this paper a battery integrated transformer-less solar PV micro-inverter with two different configurations are proposed. One of the configurations is suitable for 12/24 V battery integration, while the other configuration is suitable for 48 V battery integration. The proposed micro-inverter controls the battery current along with the current drawn from the PV module depending on the solar irradiance level and the state of charge of the battery. Though it is suitable for interfacing with a 220 V ac grid, it can operate in standalone mode as well in the absence of the grid. The leakage current remains to be zero as the micro-inverter is doubly grounded, and it is having inherent power decoupling capability. The detailed analyses of the proposed scheme is carried out. The proposed battery integrated micro-inverter under a suitable control strategy is simulated on MATLAB/Simulink platform to validate the scheme.